1. Field of the Invention
This invention relates to a circuit which generates reference frequency signals to be used in the tuning of various musical instruments, and more particularly to a reference frequency signal generator for a tuning apparatus capable of generating reference frequency signals which are based on various tuning characteristics.
2. Prior Art
Heretofore, in a musical instrument tuning apparatus, a reference frequency signal generator utilizing an analog circuit arrangement has been known in which the circuit constants of inductances (L), capacitances (C), resistances (R), etc. are varied so as to obtain various reference frequencies. Although this known generator has the advantage that the variations of the reference frequency can be made continuous, it has such disadvantages that the stability and precision of the reference frequency are low, to make it practically impossible to tune a musical instrument as accurately as within +1 cent, so that if it is desired to generate the reference frequencies in accordance with the changes of the pitch or different tuning curves, the circuit constants L, C, R, etc. need to be changed by referring to a correction value table or the like each time, which is troublesome in procedure and requires much time as well as much labor, and that since the range of the reference frequencies which can be generated is comparatively narrow, it is often required to tune a specific tone first with the tuning apparatus and thereafter to tune a desired tone with reference to the tuned specific tone so that the efficiency of the tuning job is lowered and the tuning precision as a whole is also lowered.